About
Placeholders can be used to enhance the experience of your application. They're built only with HTML and CSS, meaning you don't need any JavaScript to create them. You will, however, need some custom JavaScript to toggle their visibility. Their appearance, color, and sizing can be easily customized with our utility classes.
Example
In the example below, we take a typical card component and recreate it with placeholders applied to create a "loading card". Size and proportions are the same between the two.
Card title
Some quick example text to build on the card title and make up the bulk of the card's content.
Go somewhere<template>
<Row gutter="4">
<Col>
<Card>
<CardImgTop
src="https://dummyimage.com/100x100/20c997/20c997"
height="180"
/>
<CardBody>
<CardTitle>Card title</CardTitle>
<CardText>
Some quick example text to build on the card title and make up the
bulk of the card's content.
</CardText>
<Anchor
to="/"
tabindex="-1"
color="primary"
col="6"
>
Go somewhere
</Anchor>
</CardBody>
</Card>
</Col>
<Col>
<Card>
<CardImgTop
src="https://dummyimage.com/100x100/868e96/868e96"
height="180"
/>
<CardBody>
<CardTitle placeholder="glow">
<b-span
placeholder
col="6"
/>
</CardTitle>
<CardText placeholder="glow">
<b-span
placeholder
col="7"
/>
<b-span
placeholder
col="4"
/>
<b-span
placeholder
col="4"
/>
<b-span
placeholder
col="6"
/>
<b-span
placeholder
col="8"
/>
</CardText>
<Anchor
to="/"
tabindex="-1"
color="primary"
disabled
placeholder
col="6"
/>
</CardBody>
</Card>
</Col>
</Row>
</template>
How it works
Create placeholders with the placeholder attribute and a grid column attribute (e.g., col="6") to set the width. They can replace the text inside an element or be added as a modifier class to an existing component.
We apply additional styling to button attributes via ::before to ensure the height is respected. You may extend this pattern for other situations as needed, or add a within the element to reflect the height when actual text is rendered in its place.
<template>
<b-p
placeholder
col="6"
/>
<br />
<Anchor
to="/"
tabindex="-1"
button
color="primary"
disabled
placeholder
col="4"
/>
</template>
tip
The use of aria-hidden="true" only indicates that the element should be hidden to screen readers. The loading behavior of the placeholder depends on how authors will actually use the placeholder styles, how they plan to update things, etc. Some JavaScript code may be needed to swap the state of the placeholder and inform AT users of the update.
Width
You can change the width through grid column classes, width utilities, or inline styles.
<template>
<b-span
placeholder
col="6"
/>
<b-span
placeholder
relative-width="75"
/>
<b-span
placeholder
style="width: 25%"
/>
</template>
Color
By default, the placeholder uses currentColor. This can be overridden with a custom color or utility class.
<template>
<b-span
placeholder
col="12"
/>
<b-span
placeholder
col="12"
background-color="primary"
/>
<b-span
placeholder
col="12"
background-color="secondary"
/>
<b-span
placeholder
col="12"
background-color="success"
/>
<b-span
placeholder
col="12"
background-color="danger"
/>
<b-span
placeholder
col="12"
background-color="warning"
/>
<b-span
placeholder
col="12"
background-color="info"
/>
<b-span
placeholder
col="12"
background-color="light"
/>
<b-span
placeholder
col="12"
background-color="dark"
/>
</template>
Animation
Animate placeholders with placeholder="glow" or placeholder="wave" to better convey the perception of something being actively loaded.
<template>
<b-p placeholder="glow">
<b-span
placeholder
col="12"
/>
</b-p>
<b-p placeholder="wave">
<b-span
placeholder
col="12"
/>
</b-p>
</template>